www.nortonkit.com 18 अक्तूबर 2013
Direct links to other DC Electronics pages:
Fundamentals of Electricity: [Introduction to DC Circuits] [What is Electricity?] [Electrons] [Static Electricity] [The Basic Circuit] [Using Schematic Diagrams] [Ohm's Law]
Basic Electronic Components and Circuits. . .
Resistors: [Resistor Construction] [The Color Code] [Resistors in Series] [Resistors in Parallel] [The Voltage Divider] [Resistance Ratio Calculator] [Three-Terminal Resistor Configurations] [Delta<==>Wye Conversions] [The Wheatstone Bridge]
Capacitors: [Capacitor Construction] [Reading Capacitor Values] [Capacitors in Series] [Capacitors in Parallel]
Inductors and Transformers: [Inductor Construction] [Inductors in Series] [Inductors in Parallel] [Transformer Concepts]
Combining Different Components: [Resistors With Capacitors] [Resistors With Inductors] [Capacitors With Inductors] [Resistors, Capacitors, and Inductors]
What is Electricity?

The modern science of electricity originated with Benjamin Franklin, who began studying and experimenting with it in 1747. In the course of his experiments Franklin determined that electricity was a single force, with positive and negative aspects. Up to that point, the prevailing theory was that there were two kinds of electricity: one positive, the other negative.

To describe his experiments and results, Franklin also coined some twenty five new terms, including armature, battery, and conductor. His famous kite-flying experiment in a thunderstorm was performed in 1752, near the end of his work in this field.

Since then, many scientists, inventors, and entrepreneurs around the world have performed their own experiments, verifying and building on Franklin's beginnings in the field. Now, some 250 years later, we use electricity in almost every aspect of our daily lives. In some cases, we may not even realize that electricity is involved as an integral part of our activities.

So just what is electricity? Let's start with the dictionary definition, to give all of us some common ground. The American Heritage Dictionary actually gives four specific definitions:

Electricity

1. The class of physical phenomena arising from the existence and interactions of electric charge.
2. The physical science of such phenomena.
3. Electric current used or regarded as a source of power.
4. Intense emotional excitement.

We will skip the fourth definition as having no useful connection to the other three, and deal with electricity as a physical phenomenon which may be studied and manipulated using the tools of science.

When Ben Franklin developed his hypotheses about electricity, he arbitrarily assumed that the actual carriers of electrical current had a positive electrical charge. All of his theories, calculations, and descriptions were based on this assumption. Fortunately, his experiments still worked even with this incorrect assumption built into them. This "conventional" assumption was used for 200 years or more, and is still built into many of the common rules and procedures used to design and analyze electrical devices and behaviors.

We now know that the actual carriers of electricity are electrons, which have a negative electrical charge as defined in our system of science. Because of this, "electron theory" has been replacing "conventional theory" in schools and in regular usage.

The obvious next questions are:

1. What is an electron?
2. Where do electrons come from?
3. How do they carry an electrical charge from place to place?

We'll begin answering those questions when we take a closer look at electrons.